In circle A shown below, Segment BD is a diameter and the measure of Arc CB is 48°:
2 answers:
Answer:
66°
Step-by-step explanation:
<em>See attached picture.</em>
<em>When an angle intercepts an arc, </em><em>ARC AC</em><em>, and forms in the </em><em>center [central angle]</em><em>, the angle has </em><em>SAME</em><em> measure as the ARC AC </em><em>[denoted by x]</em><em>. When the angle formed is on the opposite side, it has a measure </em><em>HALF</em><em> of that ARC AC </em><em>[denoted ]</em>
If you look at the problem given, ∠DBC is intercepted by ARC DC and falls in the opposite side of the circle, NOT in the CENTER. <em>Hence </em><em>∠DBC</em><em> has a measure that is </em><em>HALF of ARC DC</em><em>.</em>
<em>There are </em><em>360 degrees in a circle.</em><em> </em><em>ARC DB</em><em> has 2 endpoints that are the diameter of the circle, so </em><em>ARC DB</em><em> has a measure of </em><em>180 degrees</em><em>. </em>Also,
ARC DB = ARC DC + ARC CB
ARC DB = ARC DC + 48
180 = ARC DC + 48
ARC DC = 180 - 48 = 132
Since, ∠DBC = 0.5 * ARC DC, we have:
∠DBC = 0.5 * (132)
∠DBC = 66
Our answer is the second choice of 66°.
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Our two sets of given information are that Plane <em>M </em>bisects Line <em>AB </em>and that Line <em>PA</em> is congruent to Line <em>PB</em>.
We know from the definition of a bisector that it splits a line in two equal parts. Therefore, Line <em>AO</em> must be congruent to Line <em>BO</em>.
Now, we have two sides of a triangle that we have proved to be congruent to each other. From the image given in the original problem, we see that both triangles share Line <em>OP. </em>Line <em>OP</em> is congruent to Line <em>OP</em> through the reflexive property.
We now have proven that all three sides of the one triangle are congruent to the corresponding sides on the other triangle. Therefore, the triangles are congruent through the SSS theorem.
Our two sets of given information are that Plane <em>M </em>bisects Line <em>AB </em>and that Line <em>PA</em> is congruent to Line <em>PB</em>.
We know from the definition of a bisector that it splits a line in two equal parts. Therefore, Line <em>AO</em> must be congruent to Line <em>BO</em>.
Now, we have two sides of a triangle that we have proved to be congruent to each other. From the image given in the original problem, we see that both triangles share Line <em>OP. </em>Line <em>OP</em> is congruent to Line <em>OP</em> through the reflexive property.
We now have proven that all three sides of the one triangle are congruent to the corresponding sides on the other triangle. Therefore, the triangles are congruent through the SSS theorem.